Segment Information (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Assets
Total assets	$ 17,205,770		$ 17,205,770		$ 5,758,021
Percentage of total assets	100.00%		100.00%		100.00%
Capital expenditures
Total capital expenditures	112,878	222,407	396,578	252,400
Triple-Net Leased Properties [Member]
Assets
Total assets	8,652,706		8,652,706		2,474,612
Percentage of total assets	50.30%		50.30%		43.00%
Capital expenditures
Total capital expenditures	68,604	211	69,831	12,303
Senior Living Operations [Member]
Assets
Total assets	5,807,192		5,807,192		2,297,041
Percentage of total assets	33.70%		33.70%		39.90%
Capital expenditures
Total capital expenditures	20,842	3,889	296,446	6,782
MOB Operations [Member]
Assets
Total assets	2,367,480		2,367,480		748,945
Percentage of total assets	13.80%		13.80%		13.00%
Capital expenditures
Total capital expenditures	23,432	218,307	30,301	233,315
All Other [Member]
Assets
Total assets	$ 378,392		$ 378,392		$ 237,423
Percentage of total assets	2.20%		2.20%		4.10%